activity
20212026
most citedMagnetic field and activity phenomena of the K2 dwarf V471 Tau

14 citations · 47 across the 13 of their papers we have counts for

collaborators

14 papers

astro-ph.EP2026

SPIRou near-infrared spectropolarimetry of the ultra-hot Jupiter KELT-9b: tentative detection of the planet magnetic field

Alexis Lavail, Florian Debras, David Rogé Royo +23

Exoplanetary magnetic fields govern atmospheric escape and circulation but have eluded detection in close-in planets. In the ultra-hot Jupiter KELT-9b, atmospheric dynamo is predic…

astro-ph.SR2026

The Fe I 4377 Å Line as a Solar Faculae Indicator: Insights from Spectral Ratio Analysis

Katlyn L. Hobbs, Christopher A. Watson, Jean C. Costes +21

Faculae are a dominant source of stellar activity noise in radial velocity measurements, yet their low contrast and broad surface distribution make them difficult to track in disc-…

astro-ph.SR2025

The magnetic and spin-down properties of slowly rotating fully convective M dwarfs

Victor See, Louis Amard, Stefano Bellotti +19

The evolution of the magnetism, winds and rotation of low-mass stars are all linked. One of the most common ways to probe the magnetic properties of low-mass stars is with the Zeem…

astro-ph.SR2025

Measuring the Suns radial velocity variability due to supergranulation over a magnetic cycle

Niamh K. O'Sullivan, Suzanne Aigrain, Michael Cretignier +9

In recent years supergranulation has emerged as one of the biggest challenges for the detection of Earth-twins in radial velocity planet searches. We used eight years of Sun-as-a-s…

astro-ph.EP2024

A Gaussian process model for stellar activity in 2-D line profile time-series

Haochuan Yu, Suzanne Aigrain, Baptiste Klein +3

Stellar active regions like spots and faculae can distort the shapes of spectral lines, inducing variations in the radial velocities that are often orders of magnitude larger than…

astro-ph.EP2024

Investigating stellar activity through eight years of Sun-as-a-star observations

Baptiste Klein, Suzanne Aigrain, Michael Cretignier +11

Stellar magnetic activity induces both distortions and Doppler-shifts in the absorption line profiles of Sun-like stars. Those effects produce apparent radial velocity (RV) signals…

astro-ph.EP2024★ 6 cited

Planet Hunters TESS V: a planetary system around a binary star, including a mini-Neptune in the habitable zone

Nora L. Eisner, Samuel K. Grunblatt, Oscar Barragán +61

We report on the discovery and validation of a transiting long-period mini-Neptune orbiting a bright (V = 9.0 mag) G dwarf (TOI 4633; R = 1.05 RSun, M = 1.10 MSun). The planet was…

astro-ph.EP2024★ 12 cited

TOI-837b is a Young Saturn-sized Exoplanet with a Massive 70 Core

Oscar Barragán, Haochuan Yu, Alix Violet Freckelton +10

We present an exhaustive photometric and spectroscopic analysis of TOI-837, a F9/G0 35 Myr young star, hosting a transiting exoplanet, TOI-837b, with an orbital period of 8.32d. Ut…

astro-ph.EP2024★ 7 cited

ATMOSPHERIX: III- Estimating the C/O ratio and molecular dynamics at the limbs of WASP-76 b with SPIRou

Thea Hood, Florian Debras, Claire Moutou +13

Measuring the abundances of C- and O-bearing species in exoplanet atmospheres enables us to constrain the C/O ratio, that contains indications about the planet formation history. W…

astro-ph.EP2024

Modelling stellar variability in archival HARPS data: I -- Rotation and activity properties with multi-dimensional Gaussian Processes

Haochuan Yu, Suzanne Aigrain, Baptiste Klein +4

Although instruments for measuring the radial velocities (RVs) of stars now routinely reach sub-meter per second accuracy, the detection of low-mass planets is still very challengi…

astro-ph.EP2023

ATMOSPHERIX: II- Characterising exoplanet atmospheres through transmission spectroscopy with SPIRou

F. Debras, B. Klein, J. -F. Donati +26

In a companion paper, we introduced a publicly-available pipeline to characterise exoplanet atmospheres through high-resolution spectroscopy. In this paper, we use this pipeline to…

astro-ph.EP2023

ATMOSPHERIX: I- An open source high resolution transmission spectroscopy pipeline for exoplanets atmospheres with SPIRou

B. Klein, F. Debras, J. -F. Donati +28

Atmospheric characterisation of exoplanets from the ground is an actively growing field of research. In this context we have created the ATMOSPHERIX consortium: a research project…

astro-ph.SR2022★ 8 cited

Magnetic field evolution of the K2 dwarf V471 Tau

Bonnie Zaire, Jean-Francois Donati, Baptiste Klein

Observations of the eclipsing binary system V471 Tau show that the time of the primary eclipses varies in an apparent periodic way. With growing evidence that the magnetically acti…

astro-ph.SR2021★ 14 cited

Magnetic field and activity phenomena of the K2 dwarf V471 Tau

Bonnie Zaire, Jean-Francois Donati, Baptiste Klein

We analyze spectropolarimetric data of the pre-cataclysmic variable binary system V471 Tau obtained with ESPaDOnS at the Canada-France-Hawaii Telescope in two observational campaig…